FIGURE

Fig. 3

ID
ZDB-FIG-250528-36
Publication
Rajamannar et al., 2025 - Neuropeptide oxytocin facilitates its own brain-to-periphery uptake
Other Figures
All Figure Page
Back to All Figure Page
Fig. 3

Ablation of oxytocin neurons attenuates vascular response to an osmotic challenge (A) Schema representing the transgenic Tg(oxt:Gal4;UAS:NTR-mCherry) larvae, in which oxytocin neurons express the nitroreductase (NTR) enzyme, which reduces the drug nifurpirinol (NFP) into a cytotoxic compound causing specific oxytocinergic cell death. (B and C) Tg(oxt:Gal4;UAS:NTR-mCherry) larvae were treated for 18 h with 5 μM NFP and immunostained with an antibody directed to endogenous OXT protein. NTR− (control) and NTR+ (ablated) siblings were treated with NFP, followed by anti-OXT antibody staining. Representative confocal z stack images show a reduction of OXT protein in neurohypophyseal axonal projections following NFP treatment of NTR+ larvae (B). Scale bar, 10 μm. Quantification of OXT-immunoreactive fluorescence shows a significant reduction of OXT in neurohypophyseal termini in the NTR+ cohort (C; p < 0.0001, Mann-Whitney test, control n = 19, treated n = 19). (D and E) Blood flow velocity traces representing the osmotic challenge (OC) increase in hypophyseal blood flow velocity in control (D), but not OXT-ablated (E), larvae. (F) Mean velocity after OC was increased in NTR− larvae (p = 0.0046, paired t test, n = 7) but not in their NTR+ siblings (p = 0.0947, paired t test, n = 7). (G and H) Single-sided amplitude spectra of the NTR+ cohort show no difference before and after OC as compared to the controls. (I) Variability in velocity was increased after the OC in the NTR− cohort also (p = 0.0081, paired t test, n = 7) but not in their NTR+ siblings (p = 0.5781, Wilcoxon test, n = 7). (J and K) Representative diameter traces before and after OC, showing capillary vasoconstriction of control NTR− larvae (J) compared to vasodilation of ablated NTR+ siblings (K). (L) Following OC, the hypophyseal capillary of NTR− larvae showed a decrease in diameter (p = 0.0156, Wilcoxon test, n = 7), while NTR+ larvae showed an increase in diameter (p = 0.0045, paired t test, n = 7). (M) The ratio between diameter change to basal diameter after OC was significantly different between the NTR− and NTR+ cohorts (p < 0.0001, Dunn’s multiple comparison, NTR− n = 7, NTR+ n = 7). (N–P) Mean velocity (p = 0.3941, paired t test, n = 7), variability of velocity (p = 0.6983, paired t test, n = 7), and diameter (p = 0.5249, paired t test, n = 7) of the AMCtA did not change after OC in NTR+ larvae treated with NFP. The control NTR− larvae treated with NFP also did not show any difference in mean velocity (p = 0.3095, paired t test, n = 7), variability of velocity (p = 0.5781, Wilcoxon test, n = 7), or diameter (p = 0.4430, Paired t test, n = 7) in the AMCtA after the OC. Data are represented as mean ± SEM.

Expression Data

Expression Detail
Antibody Labeling
Phenotype Data

Phenotype Detail
Acknowledgments
This image is the copyrighted work of the attributed author or publisher, and ZFIN has permission only to display this image to its users. Additional permissions should be obtained from the applicable author or publisher of the image. Full text @ Cell Rep.